nEPT: fix EPT pointer setting for L2 guest

nEPT: fix EPT pointer setting for L2 guest

Each time in virtual_vmentry(), the code needs to cover both EPT
and shadow mode for L2 guest, updating different EPT pointer to
shadow VMCS.

This fixes the issue that, launch a guest with EPT, then kill it
and launch a second guest with shadow, the second guest will hang
at the startup screen.

Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Acked by: Eddie Dong <eddie.dong@intel.com>
Committed-by: Jan Beulich <jbeulich@suse.com>